Hi Steve,

9 minutes ago, SteveW said:

The OS, Direct X, C:\Users\YOU\AppData\Local\Lockheed Martin\Prepar3D v4\Shaders, etc. etc. are all on the OS drive. P3D is a relatively small program utilising the OS and DX and so on, the size is down to the data.

The OS and Direct X are already loaded into memory before P3D is even started. The shaders are just a couple of MB. P3D is not a relatively small program: there's several hundreds of MBytes of .dll's in the main P3D folder, but it's not so much about the size of the executable + .dll's anyway because those bytes are read from disk and loaded into memory only once. There's GBytes of scenery files from scenery that's not installed on another drive; i.e. there's quite a lot of disk access performed by P3D.

 

17 minutes ago, SteveW said:

That's right Maarten, with two controllers think of two rows of people coming through one gate, there's a guy there marshalling each row through the gate in turn. RAID stripe gives you a single controller and deeper queue.

I still don't understand why you think that is true. If using one drive then yes, there's one queue with one marshaller, but the length of this queue is longer not shorter (the data request from both the OS, P3D and other applications are all going through this single queue). If using RAID the queue gets shorter (shallower) not deeper. Using RAID 0 will be faster than using two drives for sure, but one single drive without RAID will not be faster in my opinion than 2 separate drives.

thanks, Maarten

Maarten you saying all that to justify putting all the sims on different drives?

Of course RAID stripe actually works and exactly why we are beginning to see RAID more often. Look out for Intel RST enabled machines for 'bootable' RAID and consider RAID not for performance but as a backup, where if one drive fails you just shove in a replacement drive and the controller rebuilds the mirror.

Hi Steve,

No, I'm not saying that RAID does not give a performance improvement, not at all.

I think we are both talking about two different situations: I'm looking at what's the best configuration for the current hardware of Howard's setup: 120GB SSD + 512GB SSD + 1TB HD according to his signature. You are talking about a greenfield situation where you are about to go and buy new hardware. And yes, if you have the money, you should certainly consider a RAID setup.

thanks, Maarten

Yes, I thought that was fairly well cleared up, my point being in general. What we see usually is a guy whose drive is getting full and they buy a new drive. They can move the aircraft and scenery to it if they wish to free up more space, even the stock data and link it with a simple config. Uninstalling and re-installing onto the new drive not being necessary. In my opinion less drama comes from systems built up this way. Strange stuff happens to systems whereby stuff is spread all over.

 

OK, thanks for the info fellas, appreciated.

You're welcome. Well, I did a google about and the general consensus with those that tested it out is that you don't gain (or lose) performance by splitting up your sim over two drives. To actually increase drive performance requires different hardware, RAID with deeper queue. My example of a crowd passing through one gate not too intuitive but we can add a gate and we get two people in the gates at once, we doubled queue depth.

 

 

 

I don't have the technical knowledge to get into detail with you but from everything I have read from those much more technical than I - what you say is true but does not really apply to flight sims. Especially in the area of RAID. The nature of the reads and writes in a flight sim makes the RAID array not a cost effective operation. I would expect that a RAID array of SSD drives would have better performance but the amount of improvement, although statistically there is practically irrelevant - as it pertains to flight sims. 

I think we're talking about nanoseconds here not anything significant. I recall that many years ago when I was coding, I'd hand optimize the code to minimize processor cycles and improve performance. Back then, with that type of hardware, it was noticeable but with today's hardware - I seriously doubt if anyone concerns themselves with code optimization except for a few purists.

Vic

Hi Vic,

I agree with your opinion on the impact of a RAID array on the performance of a sim. It certainly helps reduce startup time, but during flight I doubt if a RAID array has a noticeable advantage.

 I do not agree however with your statement about optimizing software. Optimizing code is still very relevant. If you write a simple app that doesn't need to process large amounts of data in real time, then yes, performance is irrelevant. If you write an addon that connects with the simulator to process and present data (ActiveSky, Aivlasoft, Flightsim Commander, Plan-G or my own SimLauncherX come to mind), then performance and keeping the application responsive is very important. Look at how Chaseplane is struggling to reduce CPU-load. Hardware is always getting faster and software is always evolving to make use of these extra resources, so optimizing code remains important for any application that goes beyond 'Hello world' or Notepad.

Maarten

Good points Maarten. I've been away from coding for some years, nice to know there are still people who write and appreciate tight code.

 

Vic

If you really want an example of tight code that's IF10 and its sim messaging best in class network bandwidth, self contained installer, artwork screens, dlls all in just 10Mb.

But with talking RAID it should be considered for its reliability and ease of fault recovery as I said earlier rather than a means to improve load times. I mentioned it because newer PCs are becoming available with cheap RAID options where we only saw that in servers and high spec machines. The cost of drives should come down enough eventually to make it daft not to have a drive array with redundancy. Another option to look for is Optane you can use that as a fast cache and attach drives in RAID. If you don't have too much cash you could use HDDs which are big and cheap.

For a PC whereby you don't want to reinstall windows and apps with a failed drive choose RAID options in future.

OK fellas, then is the concensus, just to summarise, that my OS on 1) ssd and 2) P3d including all sceneries is OK on a second SSD? Which is my current setup.

Yes. Remember if you back it up there's some files on the OS drive, you might want to save the user files.

7 minutes ago, SteveW said:

Yes. Remember if you back it up there's some files on the OS drive, you might want to save the user files.

Sure, thanks Steve. I'm basically looking at installing V4 on the current SSD that has V3.4 on and then eventually get rid of V3.4 all together once I've made the move across.

Won't be any problem. Good idea, leave 3 in place for now if you got room.

Have you installed v4 yet? be careful to put into its own folder.